Conventional pincer or scissor-action wire cutters are suitable for cutting straight or gently curved wires but are not optimal for cutting coiled wires. When trimming a coiled strand with multiple individual coil turns having no gaps or gaps between adjacent individual coil turns that are smaller than the thickness of the cutter's jaws, the adjacent coil turns must be spread apart in order for the jaws to close and make the cut. If the coil turns are spread beyond their elastic limit, they will be deformed, thus damaging the coil structure.
A scissor, pincher or guillotine cut each result in a cut end which has sharp edges. It is preferable for the terminal ends of a wire or fiber which is coiled for use as a prosthetic implant to be rounded to avoid inadvertently cutting or piercing bodily tissues when placing the implant and during its use. For example, if a coiled stent has a sharp end, it could readily pierce the wall of an artery or other internal luminal structure into which it is inserted. Because the optimal dimensions of surgical prostheses are sometimes not known prior to the initial stages of surgical intervention (e.g., during visualization via radiography) either a large selection of prostheses must be kept on hand or the prosthesis must be dimensioned at the time of use. Coiled prostheses, such as stents may be trimmed to provide an optimal length. As noted, conventional cutters leave a sharp cut end and may distort a coil such as a stent. Subsequent rounding of a sharp cut end, e.g., by abrasion, represents added expense, personnel, time, complexity and apparatus to the surgical procedure and may damage the coiled structure.
It would therefore be advantageous to have a coil trimmer that minimizes the deformation of the coil from cutting and produces a cut end with a reduced tendency to cut or pierce the bodily tissues that are exposed to the cut end.